In such an inkjet image recorder, as a conveyance mechanism for a printing material, there is employed a belt conveyance mechanism that conveys a recording material in a direction orthogonal to a moving direction of a recording head by, in a state where the recording material is sucked and held on an endless belt wound on a pair of rollers including a driving motor and a driven motor, driving the driving roller.
In a system that performs printing while moving a printing material relative to the recording head by the belt conveyance mechanism, a conveyance error of the printing material is one of causes for printing unevenness. For this reason, in order to achieve stable conveyance of the printing material, there is proposed an image recorder that measures a variation in belt conveyance rate due to eccentricity of a driving roller, and on the basis of correction data based on a value obtained by the measurement, controls rotation of the driving roller (see Patent literature 1).
Further, there is also proposed an image recorder that is, in order to reduce a variation in belt conveyance rate due to, in addition to eccentricity of a driving roller, a change in thickness of an endless belt, provided with means adapted to measure a change in length from a rotating center of the driving roller to a belt surface of the endless belt, and on the basis of the change, controls rotation of the driving roller (see Patent literature 2).